Introduce AccessibilityFocusRing.

chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_
+#define CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_
+
+#include "base/basictypes.h"
+#include "base/gtest_prod_util.h"

[xiyuan, 2014/09/11 03:33:11]

nit: seems not used.

[dmazzoni, 2014/09/11 21:44:39]

Done.

+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "chrome/browser/chromeos/ui/accessibility_focus_ring_layer.h"
+#include "ui/gfx/rect.h"
+
+namespace chromeos {
+
+// AccessibilityFocusRingController manages a custom focus ring (or multiple
+// rings) for accessibility.
+class AccessibilityFocusRingController : public FocusRingLayerDelegate {
+ public:
+  // Get the single instance of this class.
+  static AccessibilityFocusRingController* GetInstance();
+
+  // Draw a focus ring around the given set of rects, in global screen
+  // coordinates.
+  void SetFocusRing(const std::vector<gfx::Rect>& rects);
+
+ protected:
+  AccessibilityFocusRingController();
+  virtual ~AccessibilityFocusRingController();
+
+  // Given an unordered vector of bounding rectangles that cover everything
+  // that currently has focus, populate a vector of one or more
+  // AccessibilityFocusRings that surround the rectangles. Adjacent or
+  // overlapping rectangles are combined first. This function is protected
+  // so it can be unit-tested.
+  void RectsToRings(const std::vector<gfx::Rect>& rects,
+                    std::vector<AccessibilityFocusRing>* rings) const;
+
+  virtual int GetMargin() const;
+
+ private:
+  // FocusRingLayerDelegate.
+  virtual void OnDeviceScaleFactorChanged() OVERRIDE;
+
+  void Update();
+
+  AccessibilityFocusRing RingFromSortedRects(
+      const std::vector<gfx::Rect>& rects) const;
+  void SplitIntoParagraphShape(
+      const std::vector<gfx::Rect>& rects,
+      gfx::Rect* top,
+      gfx::Rect* middle,
+      gfx::Rect* bottom) const;
+  bool Intersects(const gfx::Rect& r1, const gfx::Rect& r2) const;
+
+  std::vector<gfx::Rect> rects_;
+  std::vector<AccessibilityFocusRing> rings_;
+  scoped_ptr<AccessibilityFocusRingLayer> main_focus_ring_layer_;
+  std::vector<scoped_ptr<AccessibilityFocusRingLayer> > extra_layers_;
+
+  friend struct DefaultSingletonTraits<AccessibilityFocusRingController>;
+
+  DISALLOW_COPY_AND_ASSIGN(AccessibilityFocusRingController);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_